[The problems of microbial indication of water quality]. / Zur Problematik der mikrobiellen Indikation der Wasserqualität.

In three experimental series the reliability of contemporary microbial indicators has been verified. It was shown that about 30% colonies growing on the Endomedium belongs not to family Enterobacteriaceae. The share of the so-called faecal coliforms growing at 44 degrees C is 54.6%. In comparison with the initial cultivations at the second passage this part increasing at about 126%. In waters of various quality is the viability of E. coli the smallest. Also on the Mc Conkey medium at 44 degrees C disappeared the colonies in order: E. coli (3-14 days), K. pneumoniae (3-21 days) C. freundii (21-28 days). This results brings an evidence that the existing indicator system for water quality should be revised.

Elastic properties of the rat respiratory system related to age.

The experiments were performed on male rats of the Wistar strain under urethane anaesthesia (1.3 g/kg i.p.). Changes of oesophageal and tracheal pressures were registered in a group of 30 spontaneously breathing, supine rats, of 295 +/- 13 g average body weight during lung inflations with 1-5 ml of air. In another group of 25 rats of 70 +/- 6 g average body weight (young rats) we made the measurements during inflation with volumes 0.5-2 ml. The measurements were also performed in a group of 10 paralyzed, ventilated rats with 347 +/- 24 g average body weight and inflations 1-5 ml. Compliance of the lungs (CL), chest wall (CW) and of the respiratory system (Crs) was calculated from the linear part of the pressure-volume curve during inflation. The results indicate: 1. Cw is significantly (p less than 0.001) higher in young (134.7 ml.kPa-1.kg-1) than in adult rats (44.1 ml.kPa-1.kg-1). CL (related to body weight) is not significantly different in young and adult rats. 2. Cw is significantly (p less than 0.001) higher than CL. 3. No difference was observed in CLs Cw and Crs between paralyzed and spontaneously breathing animals.